bobvalli

Hi
I was driving home Wednesday in high temps (96º). Everything was good until I stopped at the last traffic light, and when I went to pull away, the tranny wouldn't upshift out of 1st. Shifting it manually and the OD button has no effect. I haven't and probably won't go to red line to see if it shifts at ultra high RPM. I cycled the shifter from (1) a little into (N) to see if the NSS had any effect.

When I got down to it, I checked codes both by scanner and the on-off-on-off-on and neither showed any codes.

'03 WJ
4.0L
42RE auto
202000 miles
previously fleet vehicle with regular maintenance
replaced TPS 12 mo ago


What I've done
checked fluid. clean and not burned. No previously noted whines .
checked vacuum line (found some cracked hoses near manifold - repaired)
replace speed sensor on outside of tranny (cheap and quick)
checked TCM fuse and relay under hood (swap test)
reseated connectors on and around ECM

Today will be kickdown cable and lever check
Hard reset of ECU
look for TCM module under dash

Anyone have any thoughts on what I've done or what I should look for next?

Any help would be most appreciated

Thanks

Bob

bobvalli

BUMP

dave1123

Sorry, but if anyone had a hard answer, I'm sure they would have done so by now.

bobvalli

Thanks Dave I was kind of getting that impression.

An update

Usually when I go after these things my strategy is to prepare a shotgun list. Research for the five most likely things to go wrong with the system I'm having trouble with, then troubleshoot from there. These are usually quick once over things without much in depth troubleshooting.

After executing my top 5 list last week I came up empty. This week I went back over the list but with more in depth troubleshooting.

Last week I did swap testing in the PDC of the fuses and relays that are connected to transmission control.

All the fuses and relays checked good. This week I retested the fuses but in addition I tested the slots in the PDC where the fuses plug in. When I metered the slots feeding the fusible link looking thing in the number 5 position of the PDC both tabs were dead. I tried testing with key off, key on, and engine running.
All the sockets around it had +12 on one of the base terminals.

Well according to the wiring diagram that 30 amp fuse feeds the base of the transmission control relay and also the B+ (+12VDC) side of the 15 amp Transmission control fuse.

I'm writing this whole thing waiting for the rain to stop so I can go out and verify what I discovered last night while digesting my days observations.

If this all meters out the way I believe it will, it will indicate a wire on the back side of the PDC burnt out. My solution will be to backfeed the base of the transmission control relay with an external fuse connected to power picked up from another location.

Wish me luck and I'll post later in the day as to whether my solution was successful or not

Bob

dave1123

I know this is PIA thing to do, but check the bottom of the PDC for loose wires or cracked solder joints. This HAS happened before.

BigBlack

I doubt I get a reply on this by now, but Bob, did you ever get any results? I'm facing the exact same issue right now, but my problem began occurring after a front end collision. It's weird, there was no body damage, and it drove fine for about 10 or 15 minutes then all of a sudden would not shift out of 1st.

dave1123

BTW, Bob, don't go looking for a TCM because it's part of the PCM now.

Gustavo Bitencourt

Hi Bob!

I have the same problem with my 00' wj.

Did you solve the problem?

dave1123

Governor pressure sensor. Mine did the same thing, then jumped to 2nd and stayed there permanently.

Gustavo Bitencourt

Did you say governor solenoid or governor sensor?

The upshift 1-2 in the 42re is only through hydraulic pressure. Is it correct? I think that mine 42re had the governor solenoid clogged.

I can't read pressure levels by the gauge on the governor port.

Thanks for your support.